The present invention relates to reducing emissions from internal combustion engines and in particular to an improved T fitting for a Positive Crankcase Ventilation (PCV) system to facilitate a flow of crankcase fumes from the crankcase and into an engine air intake.
Diesel engines are commonly used in commercial applications such as trucks and stationary engines. These engines typically have much higher compression ratios than gasoline engines, and as a result, a substantial amount of diesel blow-by escapes past the piston rings. Unlike gasoline engines which use a simple crankcase ventilation system, the diesel blow-by is generally vented to the outside, and presents a source of unpleasant fumes. Diesel engines typically can not simply vent the crankcase to the engine intake, because of the presence of the diesel blow-by includes components which are likely to degrade diesel engine performance.
U.S. patent application Ser. No. 11/330,466 for “HYDROGEN AUGMENTED DIESEL CRANKCASE VENTILATION,” a parent of the present application, discloses a system combining hydrogen and crankcase fumes in the intake of a diesel engine, whereby the hydrogen facilitates burning the crankcase fumes to reduce emissions and to improve mileage. The system of the '466 application includes a filter in the hose carrying the crankcase fumes to the engine intake. The filter both filters the fumes and traps liquids in the fumes. In some cases, the trapped liquids have filled the filter and prevented optimal operation of the system. Further, many diesel engines draw air from the intake manifold which is pumped into a tank and used to actuate, for example, air brakes. Drawing hydrogen into such a system may result in undesirable conditions.
U.S. patent application Ser. No. 11/781,826 for “HYDROGEN AUGMENTED DIESEL CRANKCASE VENTILATION,” a parent of the present application, discloses a system with a filter with a drain hose for returning the trapped liquids to the crankcase. The filter drain hose has provided a good solution to the accumulation of liquid in the filter, but some systems have shown a somewhat irregular flow of fumes from the crankcase.